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Monoclinic scheelite BiVO4 was synthesized from a mixture of aqueous Bi(NO3)3 and NH4VO3 solutions by hydrothermal method. Then using successive coating of BiVO4 with a carbon layer and a ZrO2 layer followed by heat treatment to remove the carbon layer prepared a core-shell(ZrO2@void@BiVO4) nanoparticles with a void layer between the BiVO4 core and the ZrO2 shell. TG-DTA and IR suggest that BiVO4 was coated with ZrO2. TEM shows that there was a void space between the BiVO4 core and the ZrO2 shell. The samples were characterized by XRD and the peaks of ZrO2@void@BiVO4 suits well with the pure phase monoclinic scheelite BiVO4. And its visble-light photocatalytic activity was evaluated by the photodegradation of methylene blue(MB). The results indicated that the photocatalytic activity of ZrO2@void@BiVO4 is similar to that of pure phase BiVO4, which makes it can be used for preparing liquid-gas phase boundary visble-light photocatalyst.

Abstract: A series of photocatalyst Bi1-xLaxVO4 (0.1, 0.3, 0.5, 0.7) powders were prepared by hydrothermal method. The composition, structure, morphology and photocatalytic activity of the samples were researched by means of modern testing techniques. Bi1-xLaxVO4 showed excellent visible-light sensitivity and photocatalytic activities. The degradation rate of sample with x = 0.5 on rhodamine B reached 90 %, which was much higher than that of pure BiVO4.

Abstract: Ta2O5, Ta2O5–SrO and Ta2O5–TiO2 photocatalysts were prepared by hydrothermal method and characterized using X-ray diffraction (XRD), Ultraviolet-visible Diffuse Reflectance spectroscopy (UV-Vis DRS) and Thermogravimetry (TGA). In synthesized series of TiO2-Ta2O5 catalysts, formation of anatase TiO2, hexagonal Ta2O5 and titanium tantalates were observed. For Ta2O5-SrO (Ta:Sr= 1:1) formation of mixed oxide and crystallinity was observed at calcinations temperature at 1100 °C (5hr). These synthesized catalysts were used for degradation study of methylene blue. The result demonstrated that the photocatalytic activity of the mixed oxides [Ta2O5-TiO2(1:1), Ta2O5-TiO2(2:1), Ta2O5-TiO2(1:2), Ta2O5-SrO (Ta:Sr= 1:1)] was higher than that of Ta2O5 alone.

Abstract: We report the facial synthesis of BiVO4 crystals with different morphologies by the solvothermal and hydrothermal process. The phase structure and morphology as-synthesized samples were characterized by XRD, FE-SEM, and UV-vis DRS spectroscopy. We also investigated the photocatalytic activity of BiVO4 for the decomposition of rhodamine B (RhB) under visible light irradiation. The results showed that oliver-like BiVO4 was obtained when using the mixed solvent of ethylene glycol and water while starflower-like BiVO4 was obtained using the mixed solvent of ethylene glycol monomethyl ether and water. The hydrothermal evolution process the BiVO4 product with a rod-like morphology. Oliver-like BiVO4 with pure monoclinic scheelite phase and high specific surface area exhibits efficient photodegradation of RhB (k = 7.82x10-3 min-1).